Analysis of the relationship between microstructure and mechanical properties of intercritically annealed 3.5Mn steel

The paper mainly studies intercritically annealed medium manganese steel, which only contains 3.5 wt% Mn. After annealing at different temperature, the microstructure of the experimental steel is composed of ferrite and austenite with different morphology. With the increase of intercritical annealing temperature, a small amount of martensite appears in the microstructure due to the decrease of austenite stability, and the proportion of retained austenite decreases. When the experimental steel is annealed at 700 °C, the best matching of strength and plasticity is obtained, which benefits from the appropriate proportion of austenite with different stability. The results show that excellent mechanical properties of 3.5 wt% Mn steel can be achieved by adjusting the intercritical annealing process.